Professor Lord Alton of Liverpool writes that the UK and its European allies should give a fair hearing to any appeal that the US government makes for multilateral participation in a strategy of economic and diplomatic pressures on Tehran, despite pervasive foreign and domestic threats stemming from the heart of the Iranian regime.

It is certainly no secret that Europe and the US are mired in deep disagreements over the 2015 Iran nuclear deal.

This is the reality: A career diplomat crossing European borders in a rented car while carrying a professionally-made bomb, which bears a design favored by jihadists. In Luxembourg, he hands over the bomb to two would-be terrorists, long-standing residents of Europe who just look like any ordinary young married couple.

The foreign policy establishment in the UK and throughout the world should be ready for collective action through punitive sanctions and through support for the Iranian dissidents who want to establish a free, democratic and non-nuclear Iran.

The Iranian regime has been a serious and growing menace to international peace and tranquillity for quite some time; and it remains to be one. A rift between the US and Europe regarding the fate of the nuclear agreement (the JCPOA) should not prevent them adopting a firm and robust policy vis-à-vis Iran.